proposed nutrient criteria for drinking water lakes and reservoirs in ny state cliff callinan, p.e....
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Proposed Nutrient Criteria for Drinking Water Lakes and Reservoirs in NY State
Cliff Callinan, P.E. & Ron Entringer, P.E.; NYSDECJohn Hassett, Ph.D., SUNY ESFJim Hyde, NYSDOH2013 NYC Watershed/Tifft Science & Technical Symposium
CWANYWEA
SDWA NYSAWWA
Presentation Overview
• Introduction
• Study & Methods
• Findings
• Conclusions-Recommendations
• Q & A319 September, 2013 Callinan - 2013 Watershed/Tifft
From: drjudywood.com
Learning Objectives• Understand linkages between nutrient
enrichment & potential human-health related impacts to potable water supplies (PWSs)
• Understand “linkages” between SDWA & CWA
• Discuss potential unintended consequences that may arise from certain operational changes targeted at addressing some of these issues
• Briefly review derivation of proposed numeric nutrient criteria (NNC) for PWS lakes and reservoirs
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universe-review.ca
Why the Concern w/ Nutrients & PWS?
Arsenic: cancer of bladder & kidney, as well as liver, prostate & lung
Cyanotoxins: acute toxicity (liver & nervous system), as well as possible carcinogen, also hypothetical link to ALS & other neurological disorders
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DBPs: cancer of colon & liver, as well as bladder & kidney; acute reproductive
Sediments
Algae
&
CyanobacteriaP
Leaves, humic & fulvic acids,
WWTPs, etc
Watershed Inputs
Autochthonous
NOMAllochthonous
P As
Anoxia
O2 O2
Cyanotoxins, Taste & Odor,
Filter Clogging, & Treatment Costs
Disinfection By-Products &
Treatment Costs
Arsenic,
Iron/Manganese & Treatment Costs
Harder to treat
Easier to treat
PWS Concerns
Cl2
Credit: Jim Hyde8
How Does this Happen ?
Allochthonous v. Autochthonous• Source Water Protection Perspective Allochthonous largely beyond our control Autochthonous amenable to control via nutrient
management (i.e., NNC)
• Water Treatment Perspective Allochthonous easier to remove Autochthonous hard to remove
• Tangential/Value Added Benefits Reduce unregulated DBPs Limit cyanobacteria & toxins Limit REDOX issues (e.g., As, Fe, Mn, P, etc.)
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Unintended Consequences• “Whack-a-Mole” Phenomenon
• “Chase-the-MCL” Scenario
Chloramines: N-DBPs, I-DBPs
ClO2 – Chlorite/Chlorate
• Algaecides (e.g., CuSo4) & Preox.
Potential release CB toxins
Release of DOC DBPs
• Fe & Mn Control
oxidant dose DBPs
1219 September, 2013 Callinan - 2013 Watershed/TifftFrom: Sadiq et al. (2004)
“A major challenge for water suppliers is how to balance the risks from microbial pathogens and disinfection byproducts. It is important to provide protection from microbial pathogens while simultaneously minimizing health risks to the population from disinfection byproducts.”From: http://water.epa.gov/lawsregs/rulesregs/sdwa/mdbp/index.cfm
Presentation Overview• Introduction
• Study Intro. & Methods
• Findings
• Conclusions/Recommendations
• Q & A
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Project Introduction & Disclaimer
• Project originated in response to a USEPA RFP related to development of nutrient criteria
• Project Goal: Establish nutrient criteria for potable waters in NY State protective of human health
• Presentation Disclaimer: Material presented is a work in progress and is not official NY State policy as yet !
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Institutional Acknowledgements
NYSDEC SUNY ESF Upstate Freshwater Institute
New York State Department of Health
Morgan State University Estuarine Research Center
Several Public Water Supply Systems
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Methods (THMFP & Algal Toxins)• Sampling Sampling was conducted on 21
lakes/reservoirs Monthly sampling May - October
• Laboratory Analysis Conventional Indices (P, N, Chl-a, DOC) Trihalomethane Formation Potential (THMFP) Algal Toxins (microcystin-LR,
anatoxin-a)
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Presentation Overview• Introduction
• Study Intro. & Methods
• Findings
• Conclusions-Recommendations
• Q & A
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Basic Limnology Findings
• Very good relationship observed between total phosphorus (causal variable) and chlorophyll a (response variable) - r2 ~ 0.85
Generally consistent with (NY) statewide findings as well as other investigators
Supports the hypothesis that phosphorus controls algae growth within these systems during the growing season
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Steps 1 & 2
Mean Epilimnetic Total Phosphorus vs Chlorophyll a
y = 0.6227x - 2.8074
R2 = 0.844
0
5
10
15
20
25
30
0 10 20 30 40 50
Mean Total Phosphorus (ug/l)
Mea
n C
hlor
ophy
ll a
(ug/
l)
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Disinfection By-Products Findings
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Steps 1-3 & A
commons.wikimedia.org
Overview of THMFP Results
• Seasonal increases in THMFP levels were observed in most of the systems studied
• THMFP concentrations were found to increase with increasing trophic state
• Reasonably predictive relationships were observed between trophic indices and THMFP; with r2: ~ 0.6 – 0.8
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Where to Draw the Line & Verification ?• THMFP is a “worst case” scenario
• How to compare THMFP results to real world TTHMs
• Employ off-the-shelf, peer-reviewed model
THM = f (DOC, time, dose, pH, temperature) Run 1: Verify using SMs: Observed v. Model Run 2: Use “typical” albeit conservative PWS
conditions & TTHM MCL, Solve DOCcrit.
Use DOCcrit. to solve for THMFPcrit.
Use THMFPcrit. to solve for [Chl-a] threshold
• Verification: (1) Ground-truth w/ Real World Cases & (2) Corroboration from Independent Studies
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Mean Epilimnetic Dissolved Organic Carbon vs THMFP
y = 85.298x - 58.557
R2 = 0.8021
0
100
200
300
400
500
0 1 2 3 4 5 6
Mean DOC (mg/l)
Mea
n T
HM
FP
(ug
/l)
3x MCL
2x MCL
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Mean Epilimnetic Chlorophyll a vs THMFP
y = 89.839Ln(x) + 69.03
R2 = 0.6606
0
100
200
300
400
500
0 3 6 9 12 15 18 21 24 27 30
Mean Chlorophyll a (ug/l)
Mea
n T
HM
FP
(ug
/l)
3x MCL
2x MCL
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Ground Truth Exercises (DBPs)
• Source Water Exhibiting Substantial Increase in Algal Biomass & Apparent Response in PWS 3rd Qtr. TTHM Levels
• Source Water With Moderately Elevated Algal Biomass Levels and PWS Running Annual Average TTHM Levels
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Corroborative Studies
• OECD (1982): Guidance Value [TP] < 10 ug/l
• British Columbia (1986): Guidance for water supply source water of [TP] = 10 ug/l
• Arruda & Fromm (1989): Suggested [Chl-a] = 5 ug/l threshold to meet [TTHM] = 100 ug/l
• Colorado DPHE (2012): Patterned on NY’s work (w/ enhancements); Very similar endpoint: [Chl-a] = 5 ug/l applicable to Direct Use Water Supplies (DUWS).
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From: anybodythere.net
earthfirstnews.files.wordpress.com
Algal Toxins Findings
www.usgs.gov
Steps 1-2, 6 & B
Initial Cyanotoxin Findings• Caveats: (1) No U.S. CB toxin criteria – defer to WHO
D.W. G.V. for MC-LR of 1 ug/l; (2) Additional NY Studies ongoing, but not yet fully analyzed
• Preliminary findings suggest nutrient thresholds for the control of cyanobacteria and associated toxins is somewhat higher than thresholds for DBPs. Findings also consistent w/ others (e.g., Downing, et al. 2001)
• Thus, it would appear that the thresholds derived for DBPs would also be protective for cyanobacteria and associated toxins.
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Arsenic Findings
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Steps 4-5 & C
Initial Arsenic Findings• Results indicate arsenic levels can become
elevated in hypolimnetic waters of some eutrophic lakes and reservoirs in New York during growing season
• In general, it appears that arsenic is originating from natural sources, however, its enrichment in hypolimnion is likely due to DO depletion (in part due to cultural eutrophication), and reductive release.
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Eutrophic Lake (western NY): August, 2005
0 1 2 3 4 5 6 7 8 9 10
3
4
5
5.5
6
Dep
th (
m)
Arsenic (ppb)
(MCL)
Eutrophic System (western NY) August, 2005
0
1
2
3
4
5
6
0 2 4 6 8 10
Dissolved Oxygen (mg/l)
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Presentation Overview• Introduction
• Study Intro. & Methods
• Findings
• Conclusions-Recommendations
• Q & A
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Summary of Take Home Messages• Nutrient enrichment of PWS waters can have
adverse impacts on drinking water quality
• The CWA & SDWA need to work in concert in order to best protect PWSs
• Operational changes to address one concern may lead to additional challenge(s)
• [Chl-a] < ~ 4-6 ug/l appear reasonably protective of PWS with respect to DBPs and algal toxins
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Q & A Clifford W. Callinan, P.E.
NYSDEC
625 Broadway, Albany, NY 12233-3502
(518) 402-8135
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N-Steps Web-cast (2007) http://n-steps.tetratech-ffx.com
AWWA Paper (2013)http://www.awwa.org/publications/journal-awwa/table-of-contents/issueid/36464160.aspx
AWWA Webinar 30 April, 2014